He was known for an accessible writing style that made history more interesting, typically focusing on the people in the stories as much as the events.
He was also a frequent contributor to The Sporting News, including articles to their annual publications as well as a weekly column called "Cooperstown Corner".
In that capacity, and with his substantial collection of biographical information on ballplayers (continuing Lanigan's work), he had a great deal of input to the first edition of the famous MacMillan Baseball Encyclopedia which was published in the same year he died.
[1] Although Allen had been inspired as a youth by his Hall of Fame predecessor's Baseball Cyclopedia, he was not the "figger filbert" that Lanigan was.
"[2] In addition to biographies, Allen was also a pioneer in gathering information about baseball parks, and published one of the first comprehensive lists of major league ballparks and their locations, in the 1961 edition of one of The Sporting News publications.